Currently, a cloud storage technology mainly remains at a stage where a user manages his own storage space. The user may achieve synchronization between different devices and a cloud storage server. Also, user's files in the cloud storage server may be shared. To be specific, the user may determine the file to be shared and the cloud storage server gives the user an “external link” about the file. Then, the user may provide the other users with this “external link,” through which the other users can download the file locally from the user's cloud storage space, so as to share the file.
However, when the shared file is changed in the cloud storage server, the “external link” corresponding to the shared file will be changed too. At this time, the other users cannot download the changed file from the cloud storage server through the original “external link”. Therefore, the file locally downloaded by the other users cannot be updated in synchronized with the source file.